The central focus of this project is to determine how the LVOR processes otolith and oculomotor information spatially to generate the appropriate ocular response to linear motion in any direction. We quantify the LVOR during translation along arbitrary axes to determine its accuracy and stability in 3-D. A secondary question is the nature of adaptive mechanisms that maintain the various kinematic controls in the LVOR. We hypothesize that an adaptive mechanism must exist to calibrate the relationship between LVOR responses and fixation distance. Another presumably exists to calibrate the relationship between gaze and the axis of translation in order to properly govern the NO-LVOR. We have selectively identified and quantified these processes, using both optical manipulations and lesion techniques. We have recently demonstrated, in the squirrel monkey, that the AVOR can be selectively recalibrated in a single plane. This occurs when head rotations are restricted to one plane while subjects wear magnifying optics; visual-vestibular mismatch is then limited to one plane and recalibration occurs selectively in that same plane. We will expand this approach to the LVOR and canal-otolith interactions. Future work will attempt to define the points in VOR circuitry where the AVOR and LVOR share common elements. We plan to use behavioral techniques to infer convergence of function. Canal and otolith signals have been recorded in neurons in vestibular nuclei, but the relevance of these neurons to VOR performance is unknown. We hypothesize that selective adaptation of one translational LVOR might be accompanied by parallel changes in the AVOR, implying shared (convergent) elements prior to motor neurons.